It is proposed to investigate the biosynthesis of the two microbial metabolites, compound 593A (NSC-135758) and elaiomycin. The major objectives of this work are: (a) to establish the biogenetic origin of the carbon atoms in the skeletons of 593A and elaiomycin, (b) to investigate the mechanism of chlorine introduction in 593A biosynthesis, and (c) to investigate the biogenetic origin of the azoxy function present in elaiomycin. The methods that will be utilized include: (a) the administration of specifically labeled precursors to Streptomyces griseoluteus and Streptomyces gelaticus followed by location of the labels in the metabolites via degradation or c.m.r. spectrometry and (b) precursor incorporation experiments with "doubly labeled" precursors containing carbon-14 and tritium or carbon-13 and nitrogen-15.